Allow import reassignments using as

[irh]

It's currently possible to rename imported items by reassigning them with a new name:

rng_bool = from random import bool

This isn't bad, but it becomes unwieldy when reassigning multiple items:

rng_bool, rng_number = from random import bool, number

Introducing as would allow for inline reassignment, which is more straightforward, and will be less error prone for more complex import expressions.

from random import bool as rng_bool, number as rng_number